When people stop by the tasting room they often ask me if the acres of sculpted vineyards are difficult to manage. The truth is that trellising the vines is a lengthy but crucial process. The use of a trellising method is arguably the most important tool in the grower's arsenal. The key to producing potent, flavorful berries is channeling the vine's energy into producing the fruit. Vitis vinefera is a vigorous plant and each year, if left to its own devices, will erupt into a jumbled leafy mass. But wine isn't made out of leaves. It's made out of delicious grapes. So there has to be a way to make sure that the precious energy the vine expends isn't wasted on growing more leaves than is necessary to adequately perform the photosynthesis required to nourish the plant. That's where trellising comes in. Among other things, the trellis allows the grower to restrict vegetative growth and also the fruit yield of each vine. As I mentioned last week, the trellising system also benefits the vine by creating a canopy that is evenly exposed to sunlight and is less dense. This promotes air circulation which is good for the respiration of the leaves and is also the first line of defense against mold and mildew. Over the years, humans have devised many clever and diverse ways to manipulate the shape of the vine. Although the cordon system is the most widely used in California, there are many different approaches used locally. All of these pictures were taken within a quarter mile of the Deerfield Ranch Winery.
Types of trellis systems:
The Guyot system, named for the French scientist who invented it, has become extremely popular since it was created in the 19th century. The vine is split into two arms called cordons which run horizontally in opposite directions along a wire with the shoots trained upwards.
The Vertical Shoot Positioned trellis (or VSP) is very similar to the Guyot design except that there are four arms along two different guide wires instead of two arms.
The cordon training system which also bears close resemblance to the Guyot system is the preferred method in America. All of Deerfield's organic syrah vines are trained in this fashion. One of the great benefits of this system is that it makes pruning relatively simple so that vineyard workers can perform the task perfectly with little training.
A relatively new addition to viticulture is the Scott Henry trellis, conceived of by a winemaker from Oregon. It is a variation of the VSP system where the shoots of the lower cordons are trained downward, creating two separate canopies.
The Gobblet is the oldest technique and is in declining use but it is still a core method in use throughout the Old World (especially Spain and Greece). Because there is no support system the vine takes on a bushy shape. The trunk, called the head, is pruned close to the ground and several main arms support the fruit. There are several disadvantages to this system however. It is extremely difficult to harvest the low-lying grapes. Several years ago I helped harvest a vineyard in Greece that made use of this system and my back ached for weeks after toiling hunched over all day. It also doesn't allow very good airflow and is very difficult to prune correctly.
There are many more types of trellising systems, some more exotic and creative than others. But as with most things, simplicity is often an essential element of good design. Next time you're at Deerfield take a moment to try and figure out which kind of trellis has been employed!